Question

In part (a) of the figure below, both batteries have emf = 1.33 V
and the external resistance R is a variable resistor. Part (b) of
the figure gives the electric potentials V between the terminals of
each battery as functions of R: Curve 1 corresponds to battery 1
and curve 2 corresponds to battery 2. The horizontal scale is set
by Rs = 0.20 ?.
(a) What is the internal resistance of battery 1? (b) What is the
internal resistance of battery 2?
http://www.webassign.net/hrw9/27-p-014.gif